Hydrophobically modified polyacrylamide capable of resisting interference of divalent ions and preparation method thereof

Abstract

The invention discloses hydrophobically modified polyacrylamide capable of resisting interference of divalent ions. The hydrophobically modified polyacrylamide is prepared from the following components in parts by weight: 85 to 95 parts of acrylamide, 10 to 15 parts of 2-acrylamido-2-methylpropanesulfonic acid, 10 to 15 parts of octadecyl acrylate, 5 to 8 parts of urea, 0.01 part of EDTA-2Na (Ethylene Diamine Tetraacetic Acid), 0.04 part of potassium persulfate, 0.03 part of sodium hydrogen sulfite and 377 to 380 parts of deionized water. The invention also provides a preparation method of the polyacrylamide. The polyacrylamide provided by the invention not only can resist divalent ion interference, but also has a hydrophobic modification function, so that the wastewater treatment effect can be remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a flocculant, particularly a hydrophobically modified polyacrylamide that is resistant to divalent ion interference and its preparation method. Background Technology

[0002] Polyacrylamide (PAM), a very common water-soluble polymer, plays an indispensable role in many industrial fields such as wastewater treatment, oil extraction, papermaking, textiles, and mineral processing due to its excellent flocculation, thickening, and adsorption properties. In wastewater treatment, it is a highly efficient flocculant; in oil extraction, it acts as an oil displacement agent, significantly improving crude oil recovery. This wide applicability stems from the abundance of amide groups on its molecular chain, which endow it with good water solubility and chemical activity, facilitating the acquisition of various performance derivatives through modification.

[0003] However, traditional polyacrylamide has also revealed significant technical limitations in practical applications, especially in complex water quality environments. On the one hand, when the geological environment or wastewater is rich in divalent ions (such as Ca2+),... 2+ Mg 2+ When ions of even higher valence states are present, these ions can complex with carboxyl groups and other groups on the polyacrylamide molecular chain, or undergo strong electrostatic interactions, producing a "charge shielding" effect. This causes the polymer molecular chain to curl from its extended state, reducing its hydrodynamic volume and significantly lowering its viscosity. In severe cases, flocculation and precipitation may even occur, resulting in the loss of its thickening and flocculation functions. On the other hand, conventional polyacrylamide molecules have strong hydrophilicity. When faced with wastewater systems containing oils, hydrophobic organic pollutants, or suspended particles with specific hydrophobic surfaces, their insufficient hydrophobic interaction ability often leads to unsatisfactory treatment effects in demulsification and removal of hydrophobic organic matter. Furthermore, under high-temperature conditions, the amide groups in polyacrylamide molecules are easily hydrolyzed, which also limits its application in high-temperature environments.

[0004] Therefore, there is an urgent need to develop a type of polyacrylamide that can resist interference from divalent ions and also possess hydrophobic modification properties. Combining the properties of resisting divalent ion interference with hydrophobic functionality holds promise for synthesizing highly efficient, multifunctional polyacrylamide treatment agents that can adapt to more demanding water quality conditions and target complex pollutant systems. This is of great significance for promoting technological progress and green development in related industries. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned technical problems by providing a hydrophobically modified polyacrylamide that can resist interference from divalent ions.

[0006] Another object of the present invention is to provide a method for preparing the polyacrylamide.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A polyacrylamide comprising, by weight, the following components: 85-95 parts acrylamide, 10-15 parts 2-acrylamido-2-methylpropanesulfonic acid, 10-15 parts octadecyl acrylate, 5-8 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 377-380 parts deionized water.

[0008] Preferably, the polyacrylamide comprises the following components by weight: 90 parts acrylamide, 15 parts 2-acrylamido-2-methylpropanesulfonic acid, 10 parts octadecyl acrylate, 5 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 380 parts deionized water.

[0009] Preferably, the polyacrylamide comprises the following components by weight: 85 parts acrylamide, 15 parts 2-acrylamido-2-methylpropanesulfonic acid, 15 parts octadecyl acrylate, 8 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 377 parts deionized water.

[0010] Preferably, the polyacrylamide comprises the following components by weight: 95 parts acrylamide, 10 parts 2-acrylamido-2-methylpropanesulfonic acid, 15 parts octadecyl acrylate, 5 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 380 parts deionized water.

[0011] The present invention also provides a method for preparing the polyacrylamide, which includes the following steps: S1. Dissolve acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, octadecyl acrylate, and urea in deionized water and stir until homogeneous to form a uniform monomer mixture solution; add NaOH to adjust the pH of the solution to 7-7.5. S2. Add the monomer mixture solution to the reactor and introduce nitrogen gas to remove oxygen from the system.

[0012] S3. After deoxygenation, add EDTA-2Na, potassium persulfate and sodium bisulfite to initiate the polymerization reaction. React at 50-60℃ for 6-8 hours to form a polymer colloid. S4. Granulate, dry, pulverize and sieve the colloid to obtain the polyacrylamide product.

[0013] Preferably, in step S2, the nitrogen gas is introduced for 30-60 minutes.

[0014] Preferably, in step S2, the nitrogen flow rate is 35m³ / h. 3 / h.

[0015] Compared to existing technologies, this hydrophobically modified polyacrylamide introduces octadecyl acrylate as a hydrophobic monomer, enabling it to exhibit a unique hydrophobic association effect in aqueous solutions. These hydrophobic groups aggregate due to hydrophobic interactions. When the polymer concentration exceeds the critical association concentration, intermolecular association dominates, forming a large, dynamically reversible three-dimensional physical cross-linked network. This significantly increases the polymer's hydrodynamic volume, thereby substantially increasing the solution viscosity. This physical cross-linked network composed of hydrophobic microdomains is distinctly different from covalent chemical cross-linked networks. Under high-speed shear, the network structure can be temporarily disrupted, leading to a decrease in viscosity. However, after the shearing effect is eliminated, the hydrophobic association allows the network structure to rapidly self-repair, restoring the viscosity and demonstrating excellent shear resistance. Furthermore, hydrophobic association is an endothermic, entropy-driven process; increasing temperature actually enhances the association, giving the polymer solution good temperature resistance.

[0016] In terms of resisting divalent ion interference, this polymer innovatively uses sulfonic acid groups to partially replace the carboxyl groups on the traditional polyacrylamide chain. Sulfonic acid groups have a larger hydration radius and stronger hydration capacity than carboxyl groups, and their binding constants with divalent ions such as calcium and magnesium are much lower than those of carboxyl groups. Therefore, they can effectively weaken the complexation effect between high-valent metal ions and the polymer chain, avoiding molecular chain coiling and a significant decrease in viscosity caused by "charge shielding." This structural design allows the polymer to maintain extremely high stability in environments rich in divalent ions, thus maintaining excellent flocculation or thickening properties in complex wastewater systems or harsh oil reservoir conditions. Detailed Implementation

[0017] To facilitate understanding of the present invention, a more complete description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0018] In the description of this invention, unless otherwise explicitly defined, terms such as heating, cleaning, weighing, and freezing should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0019] In the description of this invention, references to terms such as "some embodiments" and "examples" indicate that the specific methods or materials described in connection with that embodiment or example are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific methods and materials described may be combined in any suitable manner in one or more embodiments or examples.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0022] Example 1 Dissolve 90g acrylamide, 15g 2-acrylamido-2-methylpropanesulfonic acid, 10g octadecyl acrylate, and 5g urea in 380g deionized water and stir until homogeneous monomeric mixture is formed. Add NaOH to adjust the pH of the solution to 7.

[0023] The monomer mixture solution was added to the reactor, and nitrogen gas was introduced for 30 minutes, with the nitrogen flow rate controlled at 35 m³ / min. 3 / h, to remove oxygen from the system.

[0024] After deoxygenation, 0.01g EDTA-2Na, 0.04g potassium persulfate, and 0.03g sodium bisulfite were added to initiate the polymerization reaction. The reaction was carried out at 60℃ for 7 hours to form a polymer colloid.

[0025] The colloid is granulated, dried, pulverized, and sieved to obtain the polyacrylamide product.

[0026] Example 2 Dissolve 85g acrylamide, 15g 2-acrylamido-2-methylpropanesulfonic acid, 15g octadecyl acrylate, and 8g urea in 377g deionized water and stir until homogeneous monomer mixture solution is formed. Add NaOH to adjust the pH of the solution to 7.5.

[0027] The monomer mixture solution was added to the reactor, and nitrogen gas was introduced for 30 minutes, with the nitrogen flow rate controlled at 35 m³ / min. 3 / h, to remove oxygen from the system.

[0028] After deoxygenation, 0.01g EDTA-2Na, 0.04g potassium persulfate, and 0.03g sodium bisulfite were added to initiate the polymerization reaction. The reaction was carried out at 50°C for 8 hours to form a polymer colloid.

[0029] The colloid is granulated, dried, pulverized, and sieved to obtain the polyacrylamide product.

[0030] Example 3 Dissolve 95g acrylamide, 10g 2-acrylamido-2-methylpropanesulfonic acid, 15g octadecyl acrylate, and 5g urea in 380g deionized water and stir until homogeneous monomeric mixture is formed. Add NaOH to adjust the pH of the solution to 7.

[0031] The monomer mixture solution was added to the reactor, and nitrogen gas was introduced for 60 minutes, with the nitrogen flow rate controlled at 35 m³ / min. 3 / h, to remove oxygen from the system.

[0032] After deoxygenation, 0.01g EDTA-2Na, 0.04g potassium persulfate, and 0.03g sodium bisulfite were added to initiate the polymerization reaction. The reaction was carried out at 50°C for 6 hours to form a polymer colloid.

[0033] The colloid is granulated, dried, pulverized, and sieved to obtain the polyacrylamide product.

[0034] Performance testing Containing Ca 2+ Mg 2+ The simulated mine wastewater containing divalent ions was used as the treatment target. The simulated wastewater had a turbidity of 500 NTU, a suspended solids content of 1000 mg / L, and a total divalent ion concentration of 2000 mg / L.

[0035] Different amounts of polyacrylamide samples from Examples 1-3 were added to 1L of simulated wastewater, with ordinary polyacrylamide used as a control. After stirring, the mixture was allowed to settle for 30 minutes, and the turbidity and suspended solids concentration of the supernatant were measured.

[0036] Method for detecting suspended solids concentration in supernatant: GB11901-89 "Determination of suspended solids in water by gravimetric method".

[0037] Method for detecting turbidity in supernatant: GB13200-91 "Determination of turbidity in water".

[0038] The experimental data are shown in Table 1 below.

[0039] Table 1. Performance test results of polyacrylamide

[0040] Experimental results show that the wastewater treated with the polyacrylamide in Examples 1-3 of this invention has significantly lower supernatant turbidity and suspended solids concentration than wastewater treated with ordinary polyacrylamide. This demonstrates that the polyacrylamide of this invention can effectively resist divalent ion interference and achieve excellent flocculation effect.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A hydrophobically modified polyacrylamide that is resistant to divalent ion interference, characterized in that, The product comprises the following components by weight: 85-95 parts acrylamide, 10-15 parts 2-acrylamido-2-methylpropanesulfonic acid, 10-15 parts octadecyl acrylate, 5-8 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 377-380 parts deionized water.

2. The polyacrylamide according to claim 1, characterized in that, The polyacrylamide comprises the following components by weight: 90 parts acrylamide, 15 parts 2-acrylamido-2-methylpropanesulfonic acid, 10 parts octadecyl acrylate, 5 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 380 parts deionized water.

3. The polyacrylamide according to claim 1, characterized in that, The polyacrylamide comprises the following components by weight: 85 parts acrylamide, 15 parts 2-acrylamido-2-methylpropanesulfonic acid, 15 parts octadecyl acrylate, 8 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 377 parts deionized water.

4. The polyacrylamide according to claim 1, characterized in that, The polyacrylamide comprises the following components by weight: 95 parts acrylamide, 10 parts 2-acrylamido-2-methylpropanesulfonic acid, 15 parts octadecyl acrylate, 5 parts urea, 0.01 parts EDTA-2Na, 0.04 parts potassium persulfate, 0.03 parts sodium bisulfite, and 380 parts deionized water.

5. A method for preparing polyacrylamide as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Dissolve acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, octadecyl acrylate, and urea in deionized water and stir until homogeneous to form a uniform monomer mixture solution; add NaOH to adjust the pH of the solution to 7-7.

5. S2. Add the monomer mixture solution to the reactor and introduce nitrogen gas to remove oxygen from the system. S3. After deoxygenation, add EDTA-2Na, potassium persulfate and sodium bisulfite to initiate the polymerization reaction. React at 50-60℃ for 6-8 hours to form a polymer colloid. S4. Granulate, dry, pulverize and sieve the colloid to obtain the polyacrylamide product.

6. The method according to claim 5, characterized in that, In step S2, nitrogen gas is introduced for 30-60 minutes.

7. The method according to claim 5, characterized in that, In step S2, the nitrogen flow rate is 35m³. 3 / h.

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